The local people whipped themselves into a mold of cruelty. Then they formed units, squads, and armed them -- armed them with clubs, with gas, with guns. "We own the country. We can't let these Okies get out of hand." --

In the 1850s, they lynched Irishmen. In the 1870s, they terrorized the Chinese. In the first decade of the 20th century, they murdered striking Wobblies. In the 1920s, they organized "Bash a Jap" campaigns, and in the 1930s, they welcomed the Joads and other Dust Bowl refugees with teargas and buckshot.

Vigilantes have always been to the American West what the Ku Klux Klan was to the South: vicious and cowardly bigotry organized into a self-righteous mob. Almost every decade, some sinister group of self-proclaimed patriots mobilizes to repel a new invasion from some subversive threat or other.

Their wrath has almost always been directed against the poorest, most powerless and hardest-working segment of the population: recent migrants from Donegal, Guangdong, Oklahoma or, now, Oaxaca. And their rant, as broadcast daily on dozens of AM hate-radio programs in California and the Southwest, is still the one described by John Steinbeck back in the years of the Great Depression:

"Men who had never been hungry saw the eyes of the hungry. ... They said, 'These goddamned Okies are dirty and ignorant. They're degenerate, sexual maniacs. These goddamned Okies are thieves. They'll steal anything. They've got no sense of property rights.' "

The most publicized of today's vigilantes are the Minutemen, who began their armed patrol of the Arizona-Mexico border on -- appropriately enough - - April Fool's Day.

The Tombstone, Ariz., group is the latest incarnation of the anti- immigrant patrols that have plagued the borderlands for more than a decade. Vowing to defend national sovereignty against the Brown Peril, shadowy paramilitary groups, ordinarily led by racist ranchers and self-declared "Aryan warriors" and egged on by right-wing radio jocks, have harassed, illegally detained, beaten and perhaps killed immigrants crossing through the desert cauldrons of Arizona and California.

The Minuteman Project is both theater of the absurd and a canny attempt to move vigilantism into the mainstream of conservative politics. Its principal organizers -- a retired accountant and a former kindergarten teacher, both from Southern California -- mesmerized the press with their promise of a thousand heavily armed super-patriots confronting the Mexican hordes, eyeball-to-eyeball.

In the event, they turned out perhaps 150 sorry-ass gun freaks and sociopaths who spent a few days in lawn chairs cleaning their rifles and peering through binoculars at the cactus-covered mountains where several hundred immigrants perish each year from heatstroke and thirst.

Confronted with the Minutemen and the hundreds of extra Border Patrol sent to keep them out of trouble, campesinos simply waited patiently on the Sonora side for the vigilantes to get sunburned and go home. Then the normal, deadly business of the border resumed.

Yet it would be a mistake to underestimate the impact of this incident on Republican politics. For the first time, the Bush administration is feeling seriously embattled -- not by Democrats but by incipient rebellions on its own flanks.

The unpopularity of Bush's proposed privatization of Social Security has provided moderate Republicans like Colin Powell and John McCain with a wedge issue to contest the presidential succession in 2008.

More importantly, the activist grassroots of the party, especially in the West and the South, are aflame with anger about the president's proposed guest- worker treaty with Mexico, as well as his larger strategy of wooing Latino voters.

The anti-Latino backlash -- which that evil sorcerer, former California Gov. Pete Wilson, helped summon to life in the early 1990s, culminating in immigrant-bashing Proposition 187, -- has failed to quietly die as Karl Rove and other Republican strategists might have wished.

Over the last decade, instead, campaigns against immigrant social rights and the use of Spanish in schools, which originated in California, have been exported to Arizona, Colorado and Southern states with growing Latino populations.

Like earlier anti-abortion protests, which culminated in right-wing terrorism, the vigilante movement offers a dramatic tactic for capturing press attention, galvanizing opposition to immigration and shifting power within GOP.

Moreover, to the discomfort of the White House, the Minutemen have found an ardent admirer in Gov. Arnold Schwarzenegger.

If the governor sounds like he is channeling his inner Nazi, it is because he is desperate. Schwarzenegger's hulking celebrity is no longer a novelty, and he is dogged everywhere he goes these days by angry nurses, schoolteachers and firefighters whose budgets he has slashed.

In recent months, his rating in opinion polls has fallen by 20 points, and the ghost of Gray Davis shadows his future.

Not surprisingly, Schwarzenegger has returned to the same dismal swamp of hate radio and angry white guys in pickup trucks where he won the governorship in 2003. The issue then was drivers' licenses for illegal immigrants. (Otherwise, how would we know that Osama bin Laden himself wasn't tooling down the Hollywood Freeway?)

Now, it's the right of citizens to help the Border Patrol or, if need be, to render Western justice to the alien invaders.

With a vigilante man as governor, the next Minuteman provocation ("tens of thousands of volunteers blockading the Mexican border this fall") may prove to be tragedy, not farce.